Lenticular arrays or overlays are a known means to give images the appearance of depth or motion. A lenticular image is created using a transparent upper layer having narrow parallel lenticules (half cylindrical lenses) on the outer surface and an image containing substrate or lower layer which projects images through the lenticules. The two layers form a lenticular system wherein each image is selectively visible as a function of the angle from which the system is viewed. A depth image is a composite picture made by bringing together into a single composition a number of different parts of a scene viewed from different angles. When the lenticules are vertically oriented, each eye of a viewer will see different elements and the viewer will interpret the net result as depth of field. The viewer may also move his head with respect to the image thereby observing other views with each eye and enhancing the sense of depth. Each lenticule is associated with a plurality of image lines or an image line set and the viewer is supposed to see only one image line (or view slice) of each set with each eye for each lenticule. It is imperative that the line image sets be registered accurately with the lenticules, so that the proper picture is formed when the assembly is viewed.
This process can be used to generate a three-dimensional effect at a proper viewing distance or multiple images by viewing from different angles. When the lenticules are oriented horizontally, each eye receives the same image. In this case, the multiple images upon moving the lenticular can be used to generate the illusion of motion. For whichever orientation the lenticules are oriented, each of the viewed images is generated by lines from an image which has been interlaced substantially at the frequency of the lenticular array, number of lenticules per length and with the desired number of images.
One method of recording of linear images on a lenticular recording material is accomplished with a stereoscopic image recording apparatus (hereunder referred to simply as "a recording apparatus") that relies upon optical exposure (printing). With this recording apparatus, original transmission images are projected from a light source. The light transmitted through the original images passes through the projection lenses of the recording apparatus to be focused on the lenticular recording material via a lenticular sheet. The original images are thereby exposed as linear images.
Another method of image recording uses scanning exposure which requires comparatively simple optics and yet has great flexibility in adapting to various image-processing operations and to alterations in the specifications of the lenticular sheet.
In the article entitled "Development of Motion Image Printer", by H. Akahori et al., IS&T 50th Annual Conference Proceedings, page 305, there is a disclosure of a printer for printing stereoscopic images using a thermal head and thermal dye transfer in registration with the lenticular material. The receiver sheet must be heated to achieve the necessary stability for registration of the images with the lenticular material. The resolution is six images on 100 DPI lenticular material with a 300 DPI thermal head. However, there is a problem with this method in that low resolution images are obtained, since heat transferred from the resistive head "spreads" through the support during printing.
EP 0 596 629A2 and EP 0 659 026A2 disclose a method and apparatus for directly printing on lenticular supports using lasers. This method generates an image in contact with the lenticular material. There is a problem with this method, however, in that the dyes can continue to migrate after transfer, resulting in unacceptable image ghosting (adjacent views bleeding through). In addition, if it is desired to add a reflective backing to the element, then trimming or a very accurate alignment is required.
An object of this invention is to provide a process for obtaining a high resolution lenticular image which is resistant to thermal dye diffusion. It is another object of this invention to provide a process for obtaining a high resolution lenticular image which is resistant to abrasion and does not require trimming or accurate alignment. Another object of the invention is to provide a process for obtaining a high resolution lenticular image which has a reflection layer underneath the image.